1. Field of the Invention
The invention relates to a rotary sprinkler, particularly to an underground liftable low-flow sprinkler.
2. Description of the Related Art
Since the 1930s, the rotary sprinkler has been applied for the allocation of water in agricultural irrigation. Such type of patent includes U.S. Pat. Nos. 4,760,959, 4,402,460, 4,182,494, 3,955,762 and 3,022,012.
These conventional sprinklers belong to a kind of impact drive sprinkler 10 as shown in FIG. 1, comprising: a rotary shaft 11, sprinkler body 12, a nozzle 13, an impact arm 14, a reaction member 15 and a cover plate 16. The impact drive sprinkler 10 enables to circularly sprinkle an annular region. U.S. Pat. Nos. 4,182,494 and 4,760,959 further disclose an underground subterranean cylindrical housing 17 for lifting and storing the impact drive sprinkler 10.
It is found that when the conventional impact drive sprinkler 10 sprinkles, the rotation angle of the impact drive sprinkler 10 is different due to the different water pressure of the faucet, resulting in an uneven distribution of sprinkle. Moreover, the impact drive sprinkler 10 requires high water flow and high water pressure for rising up to the ground and sprinkling; therefore, it may be a waste of water resource if the high water flow does not evenly be distributed.